The invention relates generally to radiation attenuation modules and systems and more particularly to a plurality of preformed modules which are assembled into the radiation attenuation system. The modules are designed to be temporarily assembled by stacking in any desired location and alignment and can conform with irregular shapes.
In nuclear power plants and in dealing with radiation wastes in general, it is desirable to be able to put a portable or temporary shielding system in place with a minimum of exposure to the workers in placing and removing the attenuation system. The system should have maximum radiation attenuation as well as ease in utilization.
Each worker in a radiation emitting environment typically is attired in protective clothing; however, shielding is desired when the workers have to be in a radiation area for any length of time. Further the amount of exposure to each worker should be as small as possible. In a radiation area this has typically been accomplished by controlling the time of exposure and the proximity of each worker to the radiation source. Shielding influences the amount of exposure in a time period by altering the radiation environment. The shielding decreases the amount of radiation to which each worker is exposed in a time period.
Attempts to reduce the radiation exposure, such as around a reactor head during refueling operations, around boiling water generator pipes, or in waste removal, have been made. Such attempts have included placing lead shielding in the form of blankets, sheets or solid lead bricks around the radiation source or providing a frame with balloon or bag type constructions which are then filled with water. Some attempts have also been made to provide large hollow shells which are then filled with a radiation attenuation fluid. These non-integrated systems have several disadvantages including exposure between the lead members or bags. These prior art units are cumbersome to work with, generally are not free standing and are not easily adaptable to the irregular work spaces which often exist in the radiation environment.
One system which has been utilized, has been formed from a plurality of solid lead pieces and precision lead bricks. The bricks can be stacked; however, they can easily be nicked or dented, the raw uncovered lead can be contaminated, they are not deformable to fit irregular shapes and they generally are too heavy to easily be placed. Raw lead also is not compatible with the nuclear power generating environment, since it will chemically react with and contaminate stainless steel.